1. Field of the Invention
The present invention relates to a shutter device which can move shutter blades through an electromagnetic force and an elastic force so as to open or close a through-hole.
2. Description of the Related Art
With the development of the communication technology and the digital information processing technique, mobile terminals with various functions such as information processing, computing, communication, image information I/O and so on are being launched on the market.
PDAs (personal digital assistant) or mobile phones having a digital camera function and a communication function and mobile phones having a digital camera function and a PDA function can be taken as examples. With the development of the digital camera technology and information storage capacity, more and more mobile phones have a high-end digital camera module mounted thereon.
Further, as a mega-pixel image sensor is used in digital camera modules mounted on the mobile phones, the importance of a mechanical shutter device as well as an optical zoom function and an autofocusing function is emphasized.
Shutters of camera modules used in mobile phones are classified into electronic shutters and mechanical shutters.
When only the electronic shutter which is adjusted by software is used, a high-resolution photograph with a high quality cannot be expected. Therefore, more and more camera modules adopt the mechanical shutter which actually moves shutter blades to cut off unnecessary light during photographing, thereby increasing an image quality. Further, studies on a technique for reducing the size of the mechanical shutter are being actively conducted.
In the mechanical shutter, however, an electromagnet occupying a large volume is provided in the camera module, or a large number of components for implementing a complex mechanism are required. Therefore, there is a technical limit in reducing the size of the camera module.